Im doing a problem with variable frictional forces. My main equation is -mkv^2=F . We are to assume the force driving the object remains constant, kinda like a boat on the lake full bore. So, I set my F=ma equation up. -mkv^2=m(dv/dt) Next I removed m and inverted both equations to solve for dt. -dv/(kv^2)=dt Next I intetegrated both sides seperately. I was taught to use a "dummy variable" by marking v and t somehow. I simply chose to use a superscript prime marking on my paper. anyhow... Ill use a little v for real velocity and big V for dummy velocity. (1/kV)|0 to v = t Isnt that (1/kv) - (1/0) ? This equation doesnt solve nicely. In my setup I am given the equation for velocity and only asked to show how I got it. V=Vo / (1 + Vo*kt) Please help... I posted part of this problem over in classical when I had a different problem with it, so please dont flame me for double posting or spamming the board. If thats your opinion I couldnt care less. TIA to anyone who helps!